Telegraph repeater



Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE Application July 9,1937, Serial No. 152,818

19 Claims.

This invention relates to telegraph repeaters for transmission in bothdirections, one at a time, and more'particularly to repeaters of thistype which have no local current supply.

' It is among the objects of this invention to provide a simple singleline repeater which may be supplied with current over the two adjacentline sections and which will be eliicient and accurate in operation.

It is a particular object of the invention to provide a repeater of thistype in which the relays are at all times held deiinitely in eitherposition by -current over the line circuits without dependence upon thepolarizing iiux for this purpose.

@i In accordance with the invention the repeater has certain windings inthe west line sections and other 'windings in the east line sectionssupplied with current from the distant stations. The two sets ofwindings are normally opposed and tithe differential action serves tohold the contacts in marking position, thereby establishing a markingcondition in both line sections.

Proper networks are provided in connection with each line Section andare so arranged and proportioned that the current through a given set ofwindings will either be unaffected by the operation of the relaycontacts in that section in response to signals in the other section, orwill'not be reduced suiiciently to cause kick-olf lof the relay contactsin the incoming section.

The invention will now be described as applied to a particularembodiment such as the repeating system shown in the accompanyingdrawing, in which Figure l shows a two-way repeater connected betweentwo remote stations, and

Figs. 2 and 3 are schematic diagrams of onehali of the repeater inmarking and spacing positions, respectively, intended as an aid to thetheoretical consideration of the system.

Referring more particularly to Fig. 1, repeater C comprises the relays Wand E and is connected over the line section west LW to the station Aand over the line section east LE to the station B. Stations A and B maybe subscribers stations or they may be other repeater stations, such asexchange stations. At the stations A and B there is provided a set oftransmitting contacts T, which may be manually operated or may beoperated by a relay for transmitting signals over repeater C to theother station. The stations A and B further comprise a receiving windingR for reception of signals incoming from the repeater station C, forrecording or further transmission oi the signals. .l Stations A and Balso each include a source of ycurrent S. 'I'he stations A and B areserially included in the respective line circuits and contacts T arenormally closed, thereby providing a normal line current in each sectioncorresponding .to the marking condition.

(Cl. Uhn-'71) At the repeater station C the relay W is for transmissionfrom east to west and it has its main operating winding seriallyincluded in the line the contacts of relay W are included in the linewest LW and are normally operated to marking position by the operatingwinding. Similarly, E has its main winding serially included in the linewest LW and its contacts in the line east Lil. Relay W iurthermore, hasa secondary Winding included in line LW and under normal or markingconditions, the ampere turns of this winding are approximately one-halfof those of the main operating winding and the direction of currenttherethrough is such that, under marking conditions, the windings areopposed in their effect upon the armature. Under spacing conditions,when the main or primary winding is currentless, the secondary orbiasing winding will operate the armature to spacing. A similarsecondary winding is provided for relay E.

A resistance network is furthermore included in the line LW comprisingresistances lil, lI, l2, and I3. A similar network is included in theline LE and consists of the resistances 2e, 2l, 22, and 23.

The two relays of the repeater and their associated line circuits aresubstantially identical and operate in substantially identical mannersfor which reason the following discussion will be coniined totransmission in one direction only, namely, from east to west. It willbe assumed that the repeater is approximately midway between the twostations; in cases where this is not possible, it will be necessary toconsider each direction of transmission separately in designing theassociated networks.

The circuit is shown in normal or marking position in Fig. l, that iswith the transmitting contacts T and the relay contacts closed. Thecircuit from the source S at station A may now be traced as follows:from negative battery through receiving winding R, over transmittingcontacts T, upper line conductor LW, .resistance ID to point I5, atwhich the current divides into different branches. A portion of thecurrent passes through resistance il to point it. Another portion passesthrough the secondary winding oi relay W and primary winding oi relay Eto point Il, at which point this current divides, one portion goingthrough resistance I3 to point I8, the other portion through resistanceI2 to point its* where it joins the current from resistance Il andcontinues over the contacts I" relay W to point I8, where it joins thecurrent from resistance I3 and continues over lower conductor LW to thepositive side of battery S.

The line current in this circuit is suilicient to hold the relay R inmarln'ng position. The current through the left-hand windings of relaysW and VE is, however, much smaller than the line current and theserelays will be assumed to be of a more sensitive type than the relays R.

As already stated, conditions similar to those just described exist inthe right-hand portion of the circuit including the line LE so that asimilar small current ows in the right-hand winding W and E as in theleft-hand winding during the normal or marking condition.

The primary windings of relays W and E have approximately twice as mayturns as the secondary windings so that their differential effect willbe in the marking direction when the current in both sets of windings isthe same. The primary winding of relay W will be twice as strong as thesecondary winding and thus will hold the contacts safely in markingposition. Similarly, the primary winding of relay E is twice as strongas the secondary winding and holds the contacts of this relay in markingposition.

Assuming now that transmitting contacts T at station B are opened tosend a spacing impulse, the current in the line LE and in the variousbranches of the resistance networks 2L,f2I, 22, and 23, as well as inthe right-hand windings of relays W and E will reduce to zero. Relay Ewill remain unaffected in marking position, but relay W operates itsarmature to spacing by means of its secondary .vinding, which now exe'tsa :'-orce on the armature toward spacing approximately equal-to thatexerted by the previous differential effect of the two windings towardmarking.

With the contacts of relay W open the leithand circuit may now be tracedas follows:

From battery S, through winding R and contacts T at station A over theupper line LW to point I5, where the current divides, one branch flowingthrough the left-hand windings of relays W and E to point I'I and theother branch flowing through resistance networks II and I2 to point II,the two currents joining at this point and flowing through resistanceI3, over the lower line of conductor LW to battery at station A. Thus aspacing condition is impressed upon the left-hand circuit, and the linecurrent through station A is now reduced suiiiciently to insure releaseof the relay R, at station A for reception or retransmission of thespacing impulse. Under the same condition the current in the left-handwindings of relays W and E may be maintained at the same value as duringthe previously described marking condition, thereby insuring that theoperating Winding of relayE holds the contacts of relay E in markingposition and thus preventing interference with the signals incoming overthe line circuit LE. The current through the left-hand windings ofrelays W and E may, however, be reduced during spacing condition toabout half the current flowing through these windings during markingcondition, still with the desired eiect of preventing kickof of relay E,and still serving to safely lock the contacts of relay W in spacingposition. The desired currents in the line circuit through station A andthe desired currents through the lefthand windings of relays W and Eduring marking and spacing conditions, as imposed by station B, may beobtained by proper proportioning of the resistances I0, II, I2, and I3.Similar current conditions may be established in the right-hand portionof the system by proper proportioning of the resistances 20, 2I, 22, and23.

The following procedure may be used in determining the value of theseresistances and under the assumption that the relay current shouldremain substantially unaffected while the contacts in the associatedline circuit transmits to the distant station.

Referring particularly to Fig. 2, this diagram shows in simplied formcurrent paths associated with the line west LW during the transmissionof a marking impulse from the repeater to the station A and conformswith the circuits which already have been traced. Fig. 3 similarly showsin diagrammatic form the same circuit under the condition oftransmission of a spacing impulse from the repeater to station A, asalready traced above.

Thus in Fig 3 the contacts of relay W are open and the resistances I0,II, I2, and I3 form a series circuit, whereas in Fig. 2 the contacts Ofrelay W are closed, thereby bringing the points I6 and I8 together atthe same potential.

In the following discussion the resistances I0, I I, I2, and I3 will beassumed to have resistance values a, b, c, and di, respectively, Theseries resistance of the secondary winding of relay W and primarywinding of relay E has the value g. E is the voltage of the source S atstation A. Resistance a includes the line resistance and the resistanceof the apparatus at station A, included in the line circuit. I is thecurrent in the relay windings and is assumed to be the same both underspacing and marking conditions; i is the marking line current as it owsunder the condition shown in Fig. 2, and i is the spacing line currentunder the condition shown in Fig. 3.

From an inspection of the circuit in Fig. 2, we

and from Formula 2 we have cd E- ia-Ig From Formulas 3 and 4 we obtainIg(i-I)b C if-I E-a-Ig d=--- 8) By substituting these expression for cand d in the Formula 6 and solving with respect to i', We obtain(E-ia-IQE-iagI2 amperes Inserting this value of i in the expressions (7)and (8) we obtain 026,000 ohms d=48,000 ohms Thus in the assumedspecific example the sys- CII temvwillhave a marking Jinecurrent of 60milliamperes and a spacing line current of 5.13 milliamperes; aconstantcurrent of milliamperes will flow through the relay ywinding during bothmarkingand spacing impulses in the outward side ofv the repeater. Ofcourse, on that side of the system ini which the transmitting contacts Tare opened for transmission of a spacing impulse, the line current aswell as the relay current will become zero..

Thev reductionof the line current from 60 to 5.13 milliamperes issufficient to surely release relayJR at theadistant station. Bypermitting a continuous line current to flow, even during thespacing-.impulses in the output circuit of the repeater, a deniteholdingforce will be provided for the inactive relay while the otherrelay is operating, thereby preventing kick-oit and interferencewith thesignals incoming to the repeater,

-without reliance upon the natural attraction of the armature by thepolarizing flux. This continuous line current also serves to provide adenite lockingiorce for the armature in spacing position ofthe activerelay until the next marking Ilimpulse arrives.

What is claimed is:

1r A two-way telegraph repeating system comprising two line circuits,repeating contacts in each line circuit for varying the respective linecurrentsin-repeating of signals, winding means connected to said linecircuits for operating said contacts in opposite directions as signalsare incoming over one orthe other of said line circuits, saidwindingmeans remaining connected to lisaid line circuits irrespective of theoperation oi? said contacts.

2. A `two-way ltelegraph repeating system comprising two line circuits,repeating contacts in each line circuit for varying the respective line.-currents in repeating of signals, winding means connected to both linecircuits for operating each of said contacts in opposite directions inresponse to signals incoming over either of said line circuits, thecurrent in said winding means remaining substantially unaffected by theoperations of said repeating contacts.

3. A two-way telegraph repeating system ocmprising two line circuits,repeating contacts in one of said line circuits for varying the linecurrent .i inrepeating of signals, winding means connected in multiplerelation to said contacts for operating them in one direction and otherwinding means for operating said contacts in the opposite direction inresponse to signals in the other of said line circuits.

4. A telegraph signaling system comprising an east line circuit, a westline circuit, repeating relay means having active contacts in said westline circuit and inactive contacts in said east line circuit, having anoperating winding and a biasing winding connected in said west linecircuit to operate said contacts in one direction and having Windingmeans in said east line circuit to operate said contacts in the oppositedirection, resistance means interconnecting said active contacts, saidoperating and biasing windings and said west line circuit to maintainsuilicient current in said operating winding during the operation ofsaid active contacts to prevent kick-off of said inactive contacts.

5. A telegraph signaling system comprising an east line circuit, a westline circuit, west repeating relay means having active contacts in saidwest line circuit, having an operating winding connected in said eastline circuit and a biasing Winding in said west line circuit to operatesaid contacts in opposite directions, east repeating relay means havinginactive contacts in said east line circuit and having a Windingconnected in said west line circuit for operation of said inactivecontacts, and resistance means interconnecting said active contacts,said windings in the west line circuit and said west line circuit tocontinuously maintain suflicient current in said Winding of the eastrepeating relay means during the operations of said active contacts toprevent pick-oir of said inactive contacts.

6. A two-way telegraph repeating system comprising an east line circuitincluding an east current source and a west line circuit including awest current source, repeating relay means having active contacts andinactive contacts and having west windings energized by signal currentfrom said west source for operation of said contacts in one direction,and having east windings opposed to said west windings and energized bysignal current from said east source for operation oi' said contacts inthe opposite direction, resistance sections connected between. said westline circuits, west windings and active contacts to maintain suiiicientcurrent in said west windings when said active contacts are opened bysignals in said east line circuit to maintain said inactive contactsinactive.

7. A two-way telegraph repeating system comprising a west line circuit,an east line circuit, west repeating contacts and west circuit means insaid west line circuit, east repeating contacts and east circuit meansin said east line circuit, winding means connected to both of said linecircuits to operate said contacts in opposite direcH tions in responseto signals incoming over one or the other of said line circuits, saidwest circuit means being connected to said west contacts to vary thecurrent in said west line circuit for repeating of signals therein andto maintain substantially constant the current in the windings connectedin said west line circuit as said west contacts are operated in oppositedirections.

8. A two-way telegraph repeating system comprising'an east line circuit,a west line circuit, a source oi current in each line circuit, repeatingrelay means having contacts in each line circuit and having windings ineach line circuit energized by said sources to operate said contacts inopposite directions as one or the other line circuit is opened andclosed, resistance means connected in one of said line circuits to bevaried by operation of the contacts associated therewith to vary thecurrent insaidone line for transmission of signals and to maintainsuilicient current in the associated windings to prevent operation ofthe contacts in the other line circuit as said other line circuit isopened and closed.

9. A two-way telegraph repeating system comprising an east line circuit,a West line circuit, a repeater station between said line circuits, asource of signaling current in each line circuit at points remote fromsaid repeater station, said repeater station including contact means ineach line circuit, windings in each line circuit and energized by saidtwo sources of current respectively to operate one or the other of saidcontact means in opposite directions as one or the other of said linecircuits is opened and closed, and resistance means connected in one ofsaid line circuits to be varied by operations of the contact meansassociated therewith to vary the current in said one line fortransmission of signals and to maintain suiiicient current in theassociated windings to out ficiist CTI

prevent operation of the contact means in the other line circuit as saidother line circuit is opened and closed.

10. A telegraph repeater station connected between two line sectionscomprising repeating contacts in each line section, winding meansenergized over one line section for operating said contacts in onedirection and other winding means energized over the other line sectionfor operating said contacts in the opposite direction as one or theother line circuit is opened, and resistance means connected in saidline circuits to be varied by operation of said contact means forretransmission of signals without interruption of the current in saidwinding means.

11. A half-duplex telegraph repeater connected between two line circuitsand comprising retransmitting relay means having sending contacts inboth line circuits and having operating and biasing windings in bothline circuits, sources of current in both line circuits, and resistancenetworks in both line circuits connecting said windings and contacts tosaid line circuits to make said windings substantially unaffected by theoperations of said contacts.

12. A half-duplex telegraph repeater comprising two line circuits.sending contact means in each line circuit, windings permanentlyconnected in both line circuits for operating each oi said contactmeans, and a resistance network in each line circuit connecting theassociated windings and contact means to their line circuit to make allof said windings substantially unaffected by the operations of saidcontact means.

13. A telegraph repeater in accordance with claim 12 in which each ofsaid resistance networks comprises a high resistance section alternatelyconnected in multiple and series relation to said associated windings bythe operations of said associated contact means.

14. A telegraph repeater in accordance with claim 12 in which each ofsaid resistance networks comprises a low resistance section permanentlyconnected in multiple relation to said associated windings, a highresistance section permanently connected in series relation to saidassociated windings and a third resistance section alternate- 1yconnected in multiple and series relation to said associated windings bythe operations of said associated contact means.

15. A telegraph repeater in accordance with claim 12 in which each ofsaid resistance networks comprises a low resistance section permanentlyconnected in multiple relation to said associated windings, a highresistance section permanently connected in series relation to saidassociated windings and a third resistance section alternately connectedin multiple and series relation to said associated windings by theoperations of said associated contact means, the proportion of the saidthird resistance to the said low resistance being substantially equal tothe proportion of said high resistance to the total resistance includedin the associated line circuit.

16. A telegraph signaling system comprising an east line circuit, a westline circuit, a plurality of retransmitting relay means having sendingcontacts in said west line circuit and having an opelating and a biasingwinding connected in said West line circuit and winding means in saideast line circuit lor operating said contacts, and resistance meansinterconnecting said contacts, said operating and biasing windings andsaid west line circuit, to maintain a substantially constant current insaid operating and biasing windings during the operation of saidcontacts in response to signals incoming over said east line circuit.

17. A telegraph signaling system comprising an east line circuit, a Westline circuit, retransmitting relay means having sending contacts in saidwest line circuit and having a west winding connected to said west linecircuit and an east winding connected to said east line circuit foroperating said contacts in opposite directions in response to signalsincoming over said east line circuit, and resistance meansinterconnecting said contacts, said west winding and said west linecircuit to maintain a substantially constant current in said westwinding during the operations of said contacts.

18. A signal repeating system comprising an east line circuit includinga current source, a west line circuit including a current source,east-tovest repeating relay means having an operating winding in saideast line circuit and having a biasing winding and contact means in saidwest line circuit, a resistance network included in said west linecircuit and having points connected to said contact means to provide alarge current in said west line circuit in marking position and a smallcurrent in said west line circuit in spacing position of said contactmeans, the current from said west line circuit through said biasingwinding being substantially the same in the marking and spacingpositions of said contact means.

19. A signal repeating system comprising an east line circuit includinga current source, a west line circuit including a current source,eastto-West repeating relay means having contacts connected in said westline circuit, west-to-east repeating relay means having contactsconnected in said east line circuit, said repeating relay means eachhaving windings in said west and east line circuits for operation oftheir respective contacts in opposite directions in response to incoming.signal impulses, a network including a plurality of joined resistancesconnected to said west line circuit and having connections to the saidwindings in said west line circuit, said contacts of said east-to-westrelay means having connections to joining points oi said resistances tomaintain a substantially constant current in the said windings in saidwest line circuit during operation of the said contacts of the east-westrelay means in response to signals incoming over said east line circuit,thereby preventing interference with said incoming signals by thecontacts connected in said east line circuit.

FRANK H. HANLEY.

